Testing circuits



sept. 18,19%. www.

A. B. CLARK ET AL TESTING CIRCUITS 'Filed Dec. 26 1919 2 Sheets-Sheet 1W TTORNEY 'www1 2 sheets-sheet A. B. CLARK ET AL TESTING CIRCUITS FiledDec. 26 1919 Sept. 18, 1923,

INVENTORS 411/ BY/ ATTORNEY Patented Sept. 18, i923.

rarer raie i ALVA B. CLARK, OF BROOKLYN, NEW YORK, AND GEORGE CRISSON,OF HOBOKEN. NEW

JERSEY, ASSIGNORS' T0 AMERICAN CORPORATION 0F NEW YORK.

TELEPHONE AND TELEGRAPH COMPANY, A.

' TESTING erncurrs.

Appii/catfoi inea neeein'ier 2e, i919. serial No. 347,519.

To LZZ whom t may concern.' p

Be it knowfn that wfcLvA B. CLARK and Geenen Caisson, residing atBrooklyn and Hoboken, inthe counties if Kings and Hudson andV StatesofaNew York andNewJ erlsey, respectively,` have invented certain Im*proveniente in Testing Circuits, of which the following isV a.Vspecification.

This invention relates to testing circuits, particularly to circuits forthe testingV of telephone lines having repeaters associated therewith.

The arrangement'of this invention is particularly useful in testing thecircuits of phantom groups, equipped with repeaters of the type shownand described in the application by'O. B.` Blackwell for patent ontelephone repeaters filed May 29, i919,

Serialv Number 300,556. The principal chai'- acteristic novel feature ofthe invention re ides in the fact that the testing"l apparatusV isassociated with the circuits of the re- 'peeters rather than with theline conductors,

so that tests may be made as readily on the phantom as on the sidecircuits and without causing disturbances in any of the other circuitsvof the group.A

Various other features and objects of the invention will be readilyunderstood from the following description thereof having reference tothe accompanying, drawing in which Fig. l shows in diagrammatic view onespecific form. of embodiment of the invention, and Fig. 24 shows `an*application of the inventionV to a plurality of telephone circuits. l

Referring to F ig. l, Apdesignates an amplifier and K a transformer,which' together constitute avrepeater for currents in Ythe conductors L,the amplifier and transformer being associated with each other byacircuit which extends from the midpoints Vof transformer K through theamplifier to the winding @4 5 of the transformer, this circuit being`termed herein, as Vusual in the art, the local circuit o f the repeater.The connectionv of the amplifier A and vtransformer K is Vvthat commonlyknown in theV art as atwo way-one element orQl repeater.

vAssociatedwith this circuit, -in this instance i with the output of theamplifying device,

Vis akey- H, the contacts of which normally Y hold the local repeatercircuit closed.

l/Vlien, therefore, key H is in its normal l and Q of the key and wires9 and 16 into' the winding (L- of the transformer K, whereby it isreturned to the line, as well understood inthe art.

To monitor on the circuit the operator actuates the key lil'. andconnects thereby a resistance R in series with the local circuit of therepeater, so that this circuit now comprises conductor c, contact 3 ofkey H, conductor et, contacts 5 and 6 of a key il, conductor 7, contact8 of key H, conductor 9, winding zi-Z), wirel, contact 15 ofkey H, wire11i, contacts 13 and l2 of key N, resistance R, conductor l1, contact l0of key Hand conductor d. A receiver U is connected in parallel withresistance R over the normally closed contacts of the relay S, and thisreceiver responds to the voice currents in the circuit, s0 that theoperator may listen in, or monitor, on the line circuit.

The key designated N is associated'witli the normally open contacts ofthe key H. lt is provided with a right and a left set of contacts, theformer of which serves to associate a source of ringing current G withthe local circuit of tlierepeater and the latter, to associate theoperators'set T therewith, as we shall now describe.

To ring over the line, the operator leaves the key H in its operatedposition and throws the handle 0f key N to the right.

This establishes the following connections:

To talk over the line the operatorleavesV Vkey H in its actuatedposition but reverses key N so thatits left contacts are operated. Thiscauses the energization of the relay Si, current forwwhich flows overthe contact 28 of key N to ground; Relay VS in actuating its contacts`disconnects the receiver from the resistancesl` and associatesjhe saineWith the operators V1set which is new associated withv the Winding /z--b through theme- `difnno. lof the transformen B, the "connec- .tionsAascending` 'from 'terminal c throiglr conductorlG, contactl5,conduc`toi;\lf1, conftacts 13 and Q9 ofrkey N, transforirer\B,

contacts and 6 of key N, conductor 7, con,

tact 8,'conductor 9 to'terniinal Z). n,

The operator vmay thus monitor, ing or talk over the line according tothe positions lof keys-H and N. YThe key H, it will be olo 7pfservcd,'jis separate for `each telephone line, yibut, the key N andYallthelother parts of the` testing apparatus may beinade common to anynumber of lineshy connecting together theV corresponding conductors 4L,11,-7 and 14 A20 Vfroin the said lines, as indicated inthe-drawing.,Since'each of these conductors leads {to-a norinallyopen contact of thekey H, the

tcstiiig'apparatus is .associated only -Witlr thatone -of the lines,.for which thekeyl-I isk Vin an operated positionv By means of sim-'fpl'e circuits and inexpensive apparatus We are thus enabled 'toiii-agstation..

testany one of the lines The repeater described above may be any one lof-a number-of repeaters connectedY with ja `plurality of telephonecircuits, these vlati "or groups containing phantom circuits. Thislatter arrangement issliowmfor illus ytrative pur-poses only, lin Q, inffwiiich 3l and 32V represent ltwo :physical circuits Vwhich Yarelatfthesainetimeto vhe used in phantom u arrangement, The physical orVside circuit 3l has associated 'with it arrepeater which may heLof-thesocalled Ql-type, `being the same as that shownin ig-.gliandlcomprisf f Aiiig anamplifyingelement l-O., Similarly,

' fthe-physical oil side circuit 32 has a repeater` Y are alsomade'vfioin thepmidpoints -of'thef vwindings .bridged across the physical-cira cuits, Ythese connections leading directly or th-rough atransformer, torone side of theV amplifying device '42. 12As thusdescribed,

' Y comprisingthe amplifying?,- element 4l. 'In

'eachof these sidecircuitsthere areconnected windingsl, 52 and 53, 54lwhich cooperate with Windings, ffand Va repeater includ- -ing'theamplifying device 4 2. Connections the 'fcircuit is'vonewhich mayberused for phanto'nr operation and in its specific foi-.1n yfdces notconstitute apart of our invention.

; rllhecircuitis described in A:fullerdetail inf ftheBlackwellapplication-liereinbefore reoperation,

Qonnectedfwith the localcircuit of eachV amplifying device We'have shownconvenferredto 'andis 1an improvement Vin phantom* The circuit does notj c'ijinstitLite?V .arfpartof our jinyentionlhut is adapted to make useof our testingfcirfcuitandWe show it. for illustrative `purposes only.

tionally at\57,158 and@ the switch rriericlia-V` nism H of Fig. l. VAlsoWella- Ve showncon-V VVentionallyY at the V'testingapparatus of Fig. l.Bearing' infn'iind theswitching mechanism of Fig.V 1, it is seen thatthe testing apparatus lG0v isladapted to Vbecoiinected with anyone ofthe amplifying ele: ments upon suitable operation fo-fthe particulrswitch lcorresponding to that aniplif- 'ing element, and `in particularrit nh be .connected WithV the amplifier 59 of the pha torn Circuit totest this circuit Without interfering .in any Way Whatsoeierpwith r the`operation of thetroside circuits. v Y Although this`AFipjfQTillustrates` aiillar rangement adapted for pliantnijn isohViOustliat this pliantornfc replaced byV an indepen'dentpm cuit andV furtherit seeiithat its-use is not .limited to three such circuits but that an.

Vindefinite number iof Vtelephone circuits .may

ratus GO, and each or any ,one of saicl""cir cuits may be tested Ywiththesameapparatus and independent of each of the other'circuits.

be associated together-*toi thetestingfappa- Tliis'is for the rea-sonthatalltlierchanges in -the kconnection'are madefintlie local circuitVof .the repeater corresponding to thelline to, the connections to the,

he testedand not in line conductors. j

The Vinvention is not Ilimitedfto' use-With Y Y thejparticulantype ofArepeater illustrated Y v but is applicable as Welll to .other Vtypes offrepeaters, nor is; it 'limited to the'- particular p' .arrangementofappaijatus shown'he'rein, it

being readily VA understood thatV many changesV and modifications ina-yl'he made Within the scope-of the following claims Withoutfdef 'Y partingfrom the yention.

ilVhatfive-'claiIn-isl. In combination, fa line AVcircui t,-fan Yairfi-4 pliiier therefor, .and testing' apparatus'for said circuit.associated with the llocalzcir cuit of said amplifier.v

one winding in the line and anotheiiiainding lin the outputcircuit"oftheamplifier'ftest- 115V V'ing apparatus forlsaid-line-'circuit adaptedffor monitoring, .ringing or,V talking, .andV

ineans to associate the apparatus vWith said: Y

Yamplifier:and transformer "for- 'monitoring and` for .associating theapparatus Withthe transformer ande'xcludingtheamplifier vforV f ringingand talkingi 2. In'comloination, aline circuit, atWo-f p way,one=elenientlrepeater therefor Vconipris-s f 'ing anfqarnplifier andatransformer 'Withy a: z a l sociating said amplifier and selectivelyconnecting the ringing source or the source of voice current to the saidtransformer.

4. In combination, a line, a two-Way'oneelement repeater thereforcomprising an amplifying device and a transformer associated With theline and With the output of the amplifier, a source of ringing current,a telephone set, and a key for dissociating said amplifier andselectively connecting the ringing source or the telephone set to thesaid transformer.

5. In combination, a line, arepeater comprising an amplifying device anda transformer connected to said line, testing apparatus, a key forassociating `said testing apparatus with said transformer, the testingapparatus comprising a sourceV of ringing current, a telephone set, anda key for selectively associating said source or said set with saidtransformer. l

6. A testing apparatus adapted for use With a telephone line and anamplifier comprising a telephone set and a ringing source; a key forassociating said apparatus With the ampliiier and line and normallypermitting monitoring Without interruption of the talking current; andasecond key for selectively associating the set or the ringing sourceWith'the line. t

7. In combination, a line circuit, an amplifier associated therewithhaving a local circuit, a monitoring-device for-said line and means forassociating said device with said local circuit.

8. In combination, a repeater comprising an amplifying device and atransformer, a monitoring device, a 1key for at times interposing saidmonitoring device between said amplifying device and transformer, asource 0f ringing current, a talking set, and a second key fordissociating said amplifying and monitoring devices from saidtransformer and selectively associating therewith the source of ringingcurrent or the talking set.

9. In an arrangement for testing any line circuit of a phantom group,repeaters for said circuit, said repeaters having local circuits,testing devices for said line circuits,

and switching devices for selectively associ-V ating said devices Withthe local circuits of said repeaters.

10. The method of testing a line circuit Which consists in causing atransfer of energy between the line circuit and the testing devicethrough the local circuit of an amplifier. Y

In testimony whereof We have signed our names to this specification this23rd day of December, 1919.

ALVA B. CLARK. GEORGE CRISSON.`

